All $100 will get you is something the beeps and flashes and is pretty.
I got the Escort Passport 8500 X50 and I love it. The newest one, the 9500, has GPS built in, so after you pass the grocery store 5-6 times and it's the same one, and you hit the mute button, it knows to mute that frequency at that location. I speed just about everywhere I travel, and my last ticket came on a back road where the speed limit changed without a sign, so when the radar went off, I got pulled over doing 52 (when the last sign said the limit was 55) in a 30 (no signs to indicate the change, and in court, the judge said "I should've known the speed limit"....Other than that, the 8500 has saved me numerous times.